Use of response surface optimization for the production of biosurfactant from Rhodococcus spp. MTCC 2574

Area of Science:

• Microbiology
• Biotechnology
• Chemical Engineering

Background:

• Biosurfactants are amphipathic compounds with diverse applications.
• Rhodococcus species are known producers of microbial surfactants.
• Optimizing fermentation conditions is crucial for cost-effective biosurfactant production.

Purpose of the Study:

• To optimize biosurfactant production from Rhodococcus spp. MTCC 2574 using response surface methodology (RSM).
• To identify critical medium components and their optimal concentrations for enhanced yield.

Main Methods:

• Screening of seven Rhodococcus strains to select MTCC 2574.
• One-factor-at-a-time experiments to identify critical medium components (mannitol, yeast extract, meat peptone, n-hexadecane).
• Central composite rotatable design (CCRD) of RSM for optimizing component concentrations.
• Methyl tert-butyl ether extraction for crude biosurfactant recovery.

Main Results:

• RSM model showed statistical significance (R2=0.947, F=19.11).
• Optimized medium composition: mannitol (1.6 g/L), yeast extract (6.92 g/L), meat peptone (19.65 g/L), n-hexadecane (63.8 g/L).
• Biosurfactant yield increased from 3.2 g/L to 10.9 g/L (3.4-fold increase).
• Crude biosurfactant reduced water surface tension from 72 mN/m to 30.8 mN/m at 120 mg/L, with a CMC of 120 mg/L.

Conclusions:

• RSM is an effective tool for optimizing biosurfactant production.
• Optimized conditions significantly enhance yield and surface activity.
• This study provides a foundation for scalable biosurfactant production from Rhodococcus spp.